Gas sensor element and gas sensor

Abstract

A gas sensor element of the present invention detects concentration of a specific gas within a measured gas. The gas sensor element comprises: a wiring layer formed inside a sensor; an insulating layer covering a front surface of the wiring layer; an electrode terminal provided on a main surface of the insulating layer on an opposite side of the insulating layer from the wiring layer, and electrically connected to the wiring layer; and an intermediate layer interposed between the electrode terminal and the wiring layer, and electrically connecting the electrode terminal and the wiring layer. The electrode terminal is composed of a first metal material. The wiring layer is composed of a second metal material. The intermediate layer is composed of whichever of the first metal material and the second metal material has the lower melting point.

What is claimed is: 
     
       1. A gas sensor element that detects concentration of a specific gas within a measured gas, the gas sensor element comprising:
 a wiring layer formed inside the gas sensor element; 
 an insulating layer covering a front surface of the wiring layer; 
 an electrode terminal provided on a main surface of the insulating layer on an opposite side of the insulating layer to the wiring layer, and electrically connected to the wiring layer; 
 an intermediate layer interposed between the electrode terminal and the wiring layer, and electrically connecting the electrode terminal and the wiring layer; and 
 a metal connecting member having electrical conductivity, 
 wherein the insulating layer is provided with a through hole formed to pass through the insulating layer, the metal connecting member is disposed within the through hole, the through hole has a smaller outer diameter than that of the intermediate layer, and the metal connecting member electrically connects the intermediate layer and the electrode terminal, wherein 
 the connecting member and the electrode terminal are composed of a first metal material, the wiring layer and the intermediate layer are composed of a second metal material, and the second metal material is lower in melting point than the first metal material. 
 
     
     
       2. The gas sensor element according to  claim 1 , wherein
 a void is formed in the peripheral portion of the intermediate layer that is the periphery of an interface with the intermediate layer that is in contact with the connecting member composed of a metal material differing from that of the intermediate layer. 
 
     
     
       3. The gas sensor element according to  claim 1 , wherein
 a relationship B/A≧2 is established between an outer diameter A of the through hole and an outer diameter B of the intermediate layer, and a thickness d of the intermediate layer is 0.01 mm or more. 
 
     
     
       4. A gas sensor including a gas sensor element according to  claim 3 . 
     
     
       5. A gas sensor element that detects concentration of a specific gas within a measured gas, the gas sensor element comprising:
 a wiring layer formed inside the gas sensor element; 
 an insulating layer covering a front surface of the wiring layer; 
 an electrode terminal provided on a main surface of the insulating layer on an opposite side of the insulating layer to the wiring layer, and electrically connected to the wiring layer; 
 an intermediate layer interposed between the electrode terminal and the wiring layer, and electrically connecting the electrode terminal and the wiring layer; 
 a first through hole that passes through the insulating layer, has a metal first connecting member disposed within, has a smaller outer diameter than the intermediate layer, and connects the intermediate layer and the electrode terminal; and 
 a second through hole that passes through the insulating layer, has a metal second connecting member disposed within, has a smaller outer diameter than the intermediate layer, and connects the wiring layer and the intermediate layer, wherein 
 the first connecting member and the electrode terminal are composed of a first metal material, the wiring layer and the second connecting member are composed of a second metal material, and the intermediate layer is composed of whichever of the first metal material and the second metal material has the lower melting point. 
 
     
     
       6. The gas sensor element according to  claim 5 , wherein
 a void is formed in the peripheral portion of the intermediate layer that is the periphery of an interface with the intermediate layer that is in contact with the connecting member composed of whichever of the first metal material and the second metal material has the higher melting point. 
 
     
     
       7. The gas sensor element according to  claim 5 , wherein
 a void is formed in the peripheral portion of the intermediate layer that is the periphery of an interlace with the intermediate layer that is in contact with the connecting member composed of whichever of the first metal material and the second metal material has the higher melting point, 
 wherein 
 a relationship B/A≧2 is established between an outer diameter A of the first through hole and an outer diameter B of the intermediate layer, 
 a relationship B/A≧2 is established between an outer diameter A of the second through hole and an outer diameter B of the intermediate layer, 
 and a thickness d of the intermediate layer is 0.01 mm or more. 
 
     
     
       8. A gas sensor including a gas sensor element according to  claim 7 . 
     
     
       9. The gas sensor element according to  claim 5 , wherein
 a void is formed in the peripheral portion of the intermediate layer that is the periphery of an interface with the intermediate layer that is in contact with the connecting member composed of a metal material differing from that of the intermediate layer. 
 
     
     
       10. The gas sensor element according to  claim 5 , wherein
 a relationship B/A≧2 is established between an outer diameter A of the through hole and an outer diameter B of the intermediate layer, and a thickness d of the intermediate layer is 0.01 mm or more.